Carpal tunnel syndrome (CTS) is a painful condition of the hand characterized by tingling and numbness and loss of grip strength. CTS is caused by the compression of the median nerve at the carpal tunnel and it is one of the common nerve entrapment syndromes.
As shown in FIG. 1, which illustrates a normal or non-compressed carpal tunnel, the carpal tunnel 5 is the area of the wrist and palm of the hand 10 formed by a U-shaped cluster of bones 15 that form a hard floor and two walls of the tunnel 5. The roof of the tunnel is formed by the transverse carpal ligament (TCL) 20 which attaches to the wrist bones. Within the confines of the tunnel 5 is the median nerve 25 and the flexor tendons 30 of the thumb and fingers.
As indicated in FIG. 2, which depicts a compressed carpal tunnel, a thickening of the TCL 20 and a corresponding narrowing of the size of the carpal tunnel 5 may precipitate CTS. This thickening causes compression of the flexor tendons 30 and median nerve 25 which leads to CTS symptoms.
A number of factors may contribute to the thickening of the TCL. Normal wear and tear and repetitive wrist movements may cause thickening of the TCL. Wrist fracture may cause bony narrowing of the tunnel. Pregnancy, obesity, diabetes, thyroid dysfunction and chronic renal failure may predispose a patient to CTS. CTS generally occurs in people between the ages of 30 and 60 and it is more common in females.
Diagnosis of CTS may be established by history and examination. Symptoms may include nocturnal hand pain. Positive examination findings include nerve irritation signs, such as positive Phalen's wrist flexion test, and Tinel's sign, and weakness and numbness in the median nerve distribution. Electrical studies show prolongation of about 3.5 milliseconds is present in many surgically confirmed cases.
Medical management may be by splinting, anti-inflammatories, and steroid injections in the wrist. If unsuccessful, surgical intervention to decompress or release the TCL may be indicated.
FIG. 3 depicts one type of surgical technique, known as an open release surgery. Open surgical decompression by cutting the TCL was first described in 1930 by Learmonth. The open technique involves creation of an incision beginning in the palm and extending to the wrist. Through this open incision, a surgeon may directly visualize the TCL and may use a scalpel to cut completely through the TCL and release the compression of the median nerve. Angling the incision towards the ulnar aspect of the wrist helps to avoid cutting the palmar sensory cutaneous branch of the median nerve. The skin incision can vary in length from one to five inches depending upon training and experience but should be sufficient to allow full sectioning of the TCL.
After surgery, the hand is wrapped. The stitches are removed 10 to 14 days after surgery. Patients may be directed to wear a splint for several weeks. The pain and numbness may go away right after surgery or may take several months to subside.
However, open incisions require significant time to heal. Also, the skin in the palm is thick and prone to cracking and hand immobilization is necessary for wound healing. Patients are often advised to avoid heavy use of their hand for up to 3 months. When a patient's return to work is dependent on the operated hand, rehabilitative physical therapy is commonly prescribed. Therapy is often prescribed for the resultant symptomatic scar tissue.
FIG. 4 depicts another type of surgical technique known as an endoscopic release surgery. Endoscopic carpal tunnel release is a technical procedure that requires microscopic techniques and the correct endoscopic equipment with the necessary back up equipment.
To perform the procedure, anesthetic is administered and an incision is marked out on the wrist just proximal to the palm. The superficial tendon and small veins are retracted to prevent nerve injury. An ‘L’ or ‘U’ shaped incision is made in the first layer called the flexor retinaculum. This layer is lifted up as a flap that forms a doorway into the carpal tunnel.
A spoon shaped device (such as a synovial elevatoris) is used to clean the under surface of the ligament to provide visualization with an endoscope. Dilators help to compress the tissues in the carpal canal to make it possible to insert the endoscopic device with minimal pressure. The endoscopic device is inserted carefully so that the ligament can be seen along its entire length. Often the device is warmed to prevent fogging. Once the ligament is clearly seen, the small blade in the device is used to release the ligament in stages, after making sure that important nerves and arteries are protected.
Once the ligament is completely released, the rest of the flexor retinaculum in the wrist is released with a special type of scissors. Local anesthetic is injected for post-operative pain relief and the incision is sutured. A soft bandage is applied for the patient to keep on for two days to reduce swelling. After two days they can remove the larger dressing and apply a Band-Aid.
This method requires specialized training and a long learning curve. Surgery is longer than the open release procedures and significant injuries have been reported.
Plantar fasciitis is a painful inflammatory process of the plantar fascia. The plantar fascia is a thick fibrous band of tissue originating at the bottom surface of the calcaneus (heel bone) and extending along the sole of the foot towards the toes. According to one study, plantar fasciitis occurs in two million Americans a year and will occur in 10% of the population over a lifetime. Plantar fasciitis is commonly associated with long periods of work-related weight bearing activity, and among non-athletic populations, it is associated with a high body mass index. Typically, pain is felt on the underside of the heel and one may suffer from decreased dorsiflexion of the ankle in addition to knee pain. Generally, treatment is non-surgical, although surgical treatment may be used. One type of surgical technique may include use of an ultrasound guided needle. The needle is inserted into the plantar fascia and moved back and forth to disrupt the fibrous tissue. Another surgical technique is a coblation surgery (also known as a Topaz procedure). This technique has been used in the treatment of recalcitrant plantar fasciitis and utilizes radiofrequency ablation.
Stenosing tenosynovitis (commonly known as trigger finger) is a painful condition of the finger or thumb characterized by the finger or thumb becoming locked in a bent position and straightening with a snap. Trigger finger is caused by inflammation of the tenosynovium that surrounds the tendon of the affected finger or thumb.
Cubital tunnel and Guyon's canal syndrome are painful conditions of the elbow characterized by numbness, tingling, and a loss of strength. With cubital tunnel syndrome, the ulnar nerve is compressed by the humerus bone. Guyon's canal syndrome is compression of the ulnar nerve, by, for example, a cyst or a ligament, e.g., the volnar radio-ulnar ligament.
Known surgical techniques may cause injury to the nerve, infection and may fail to relieve the pain.
There is a need in the art for improved systems and methods for surgical treatment of carpal tunnel syndrome, plantar fasciitis, cubital tunnel syndrome and similar afflictions with increased efficiency and reduced surgical complications.